Provisioning customized virtual machines without rebooting

ABSTRACT

Embodiments provision and customize virtual machines (VMs), such as desktop VMs, without rebooting the desktop VMs. In response to a request to provision the VMs, a computing device creates a clone VM from a parent VM template identified in the request. One or more customization that prompt rebooting of the clone VM are applied to the clone VM. The computing device instantiates a plurality of child VMs from the customized clone VM. A child VM configuration is applied to at least one of the instantiated child VMs without provoking a reboot of those child VMs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. patent applications entitled“Elastic Compute Fabric Using Virtual Machine Templates”, “FastInstantiation of Virtual Machines”, and “State Customization of ForkedVirtual Machines”, filed concurrently herewith, all of which areincorporated by reference herein in their entireties.

BACKGROUND

Some existing systems allow creation of virtual desktops using linkedclones, such as with the View Composer feature in the Virtual DesktopInfrastructure (VDI) product by VMware, Inc. In such systems, thevirtual desktops share a common base image residing on their parent VM'sbase disk but each virtual desktop has its own delta disk. This storageconsolidation enables customers to reduce the storage cost for theirvirtual deployment. However, the size of the delta disk grows over time.This not only discounts the storage savings brought by the base diskconsolidation, but also deteriorates the runtime disk accessperformance.

Some of the existing systems attempt to mitigate delta disk growth byredirecting user data and system temporary content to separate disks,and/or allowing the delta disk to revert to checkpoint images when thedelta disk grows to a particular size. However, customizing each of thevirtual desktops to enable such mitigations is time-consuming. Further,applying the customizations often requires at least two rebootoperations that further slow the virtual desktop provisioning process,and negate the benefits of fast instantiation of the virtual desktops.The reboot threats arise, for example, from operations performed on eachof the virtual desktops. For example, the first reboot operation mayoccur when setting a computer name and activating a license. The secondreboot operation may occur when joining a domain, performingcheckpointing operations, and/or responding to reboot requests from adevice manager executing on the virtual desktop (e.g., to install devicedrivers for added disks).

Performing two full reboot cycles during guest customization of eachdesktop clone negatively affects performance. In large scaleprovisioning of thousands of virtual desktops using the existingsystems, for example, the reboot cycles aggravate boot storm levels(e.g., a peak surge of memory utilization) which cause elevatedinput/output operations per second (IOPS) at the storage layer therebypreventing customers from realizing storage savings from the storageconsolidation of using linked clone VMs. Additional storage may bepurchased, but this only increases cost for the consumer. In addition,when rebooting, each virtual desktop loses the benefit of memory pagesharing with a parent virtual machine such that “instant” instantiationis not available.

Further, with the existing systems, the additional time to prepare thevirtual desktops increases the overall provisioning time, which mayleave the system vulnerable to any transient environment issue therebyincreasing the failure rate and cost of ownership by the customer.

SUMMARY

One or more embodiments described herein configure a parent virtualmachine (VM) template before instantiating child VMs therefrom toprevent rebooting the child VMs during subsequent guest customization. Acomputing device receives a request to provision a plurality of childVMs. The request identifies a parent VM template. In response to thereceived request, the computing device creates a clone VM from theparent VM template and applies one or more customizations that promptrebooting of the clone VM. A plurality of child VMs are theninstantiated from the customized clone VM. A child VM configuration isapplied to at least one of the instantiated plurality of child VMswithout rebooting that child VM.

In some embodiments, the child VMs are desktop VMs provisioning across aplurality of target hosts. The computing device maintains a replica mapthat stores an assignment between each of a plurality of clone VMs andat least one of the target hosts.

This summary introduces a selection of concepts that are described inmore detail below. This summary is not intended to identify essentialfeatures, nor to limit in any way the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary host computing device.

FIG. 2 is a block diagram of virtual machines (VMs) that areinstantiated on a computing device, such as the host computing deviceshown in FIG. 1.

FIG. 3 is a block diagram of an exemplary computing device in a cloudplatform storing VM templates and data describing VMs instantiatedtherefrom.

FIG. 4 is a flowchart of an exemplary method (e.g., performed by thecomputing device in FIG. 3) to create a customized clone VM beforeinstantiating child VMs therefrom.

FIG. 5 is a flowchart of an exemplary method (e.g., performed by thecomputing device in FIG. 3) to attach one or more disks to a clone VMbefore instantiating desktop VMs.

FIG. 6 is a block diagram of an exemplary cloud platform for attachingone or more disks to a clone VM before instantiating desktop VMs.

FIG. 7 is a block diagram illustrating replication of a customized cloneVM to datastores of target hosts.

FIG. 8 is a flowchart of an exemplary method for using a replica map toidentify, or create, a customized clone VM from which to instantiatedesktop VMs on a target host.

FIG. 9 is a block diagram illustrating instantiation of child VMs from aparent VM.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Embodiments described herein instantiate a plurality of virtual machines(VMs), such as desktop VMs, without rebooting. Some embodimentsconsolidate customizations that prompt reboots into a single clone VM,which is then shared with the desktop VMs. Each of the desktop VMs thenpower-on without rebooting. For example, while data redirection toexternal disks presents a reboot threat in some existing systems,aspects of the disclosure eliminate the reboot threat from dataredirection at each desktop VM. Exemplary operations that areconsolidated in the single clone VM include, but are not limited to,adding and/or creating a user data disk, adding and/or creating a systemdisposable disk, partitioning the disks, formatting the disks, and/orassigning mount points for the disks. Aspects of the disclosureconfigure the desktop VMs to redirect data to other disks, such as theuser data disk and/or the system disposable disk, to reduce disk spacewithin each desktop VM.

Accordingly, aspects of the disclosure enable the desktop provisioningprocess to achieve customization without a single reboot at theindividual desktop clone level. Eliminating reboot cycles enablesaspects of the disclosure to perform fast instantiation routines thatuse memory page sharing, such as the forking routines described herein.While aspects of the disclosure are operable with any fast instantiationroutines, some embodiments are operable with forking operations asdescribed herein. Forking instantly creates live child VMs from apowered-on parent VM. This offers instant live VM provisioning withunderlying memory and disk resource sharing.

Further, by powering on each child VM directly from the forking point ofa parent VM, the initial boot process at each child VM is simplified,requires less time, and significantly reduces boot storms. This isespecially effective when customizing a large quantity of desktop VMs.Further, storage costs (and other ownership costs) for customers arereduced based on, for example, a reduction in input/output operationsper second (IOPS) demand at the storage array level. Memory costs arealso reduced when using the forking operations because of memory pagesharing between the child VMs and the parent VMs. For short-lived,non-persistent desktop VMs, the memory page sharing may occur during theentire lifecycle of such desktop VMs. Additionally, employing forkingwithout rebooting the child VMs accelerates initial deployment oflinked-clone VMs, which can then be converted to full-clone VMs (e.g.,by migrating the linked-clone VMs to full-clone status while thelinked-clone VMs are already being used by the customers). This presentsa more efficient way of provisioning or relocating full VMs.

Aspects of the disclosure further enable simplified checkpointing. Forexample, rather than rebooting each desktop VM when creating acheckpoint image, the file system in the desktop VM is quiesced toenable copying of an operating system delta disk.

Some embodiments operate within a virtual desktop provisioninginfrastructure, such as the Virtual Desktop Infrastructure (VDI) productby VMware, Inc. However, such embodiments are operable with any virtualdesktop provisioning infrastructure.

An exemplary virtualized environment is next described.

FIG. 1 is a block diagram of an exemplary host computing device 100.Host computing device 100 includes a processor 102 for executinginstructions. In some embodiments, executable instructions are stored ina memory 104. Memory 104 is any device allowing information, such asexecutable instructions and/or other data, to be stored and retrieved.For example, memory 104 may include one or more random access memory(RAM) modules, flash memory modules, hard disks, solid state disks,and/or optical disks.

Host computing device 100 may include a user interface device 110 forreceiving data from a user 108 and/or for presenting data to user 108.User 108 may interact indirectly with host computing device 100 viaanother computing device such as VMware's vCenter Server or othermanagement device. User interface device 110 may include, for example, akeyboard, a pointing device, a mouse, a stylus, a touch sensitive panel(e.g., a touch pad or a touch screen), a gyroscope, an accelerometer, aposition detector, and/or an audio input device. In some embodiments,user interface device 110 operates to receive data from user 108, whileanother device (e.g., a presentation device) operates to present data touser 108. In other embodiments, user interface device 110 has a singlecomponent, such as a touch screen, that functions to both output data touser 108 and receive data from user 108. In such embodiments, userinterface device 110 operates as a presentation device for presentinginformation to user 108. In such embodiments, user interface device 110represents any component capable of conveying information to user 108.For example, user interface device 110 may include, without limitation,a display device (e.g., a liquid crystal display (LCD), organic lightemitting diode (OLED) display, or “electronic ink” display) and/or anaudio output device (e.g., a speaker or headphones). In someembodiments, user interface device 110 includes an output adapter, suchas a video adapter and/or an audio adapter. An output adapter isoperatively coupled to processor 102 and configured to be operativelycoupled to an output device, such as a display device or an audio outputdevice.

Host computing device 100 also includes a network communicationinterface 112, which enables host computing device 100 to communicatewith a remote device (e.g., another computing device) via acommunication medium, such as a wired or wireless packet network. Forexample, host computing device 100 may transmit and/or receive data vianetwork communication interface 112. User interface device 110 and/ornetwork communication interface 112 may be referred to collectively asan input interface and may be configured to receive information fromuser 108.

Host computing device 100 further includes a storage interface 116 thatenables host computing device 100 to communicate with one or moredatastores, which store virtual disk images, software applications,and/or any other data suitable for use with the methods describedherein. In exemplary embodiments, storage interface 116 couples hostcomputing device 100 to a storage area network (SAN) (e.g., a FibreChannel network) and/or to a network-attached storage (NAS) system(e.g., via a packet network). The storage interface 116 may beintegrated with network communication interface 112.

FIG. 2 depicts a block diagram of virtual machines 2351, 2352 . . . 235Nthat are instantiated on host computing device 100. Host computingdevice 100 includes a hardware platform 205, such as an x86 architectureplatform. Hardware platform 205 may include processor 102, memory 104,network communication interface 112, user interface device 110, andother input/output (I/O) devices, such as a presentation device 106(shown in FIG. 1). A virtualization software layer, also referred tohereinafter as a hypervisor 210, is installed on top of hardwareplatform 205.

The virtualization software layer supports a virtual machine executionspace 230 within which multiple virtual machines (VMs 2351-235N) may beconcurrently instantiated and executed. Hypervisor 210 includes a devicedriver layer 215, and maps physical resources of hardware platform 205(e.g., processor 102, memory 104, network communication interface 112,and/or user interface device 110) to “virtual” resources of each of VMs2351-235N such that each of VMs 2351-235N has its own virtual hardwareplatform (e.g., a corresponding one of virtual hardware platforms2401-240N), each virtual hardware platform having its own emulatedhardware (such as a processor 245, a memory 250, a network communicationinterface 255, a user interface device 260 and other emulated I/Odevices in VM 2351). Hypervisor 210 may manage (e.g., monitor, initiate,and/or terminate) execution of VMs 2351-235N according to policiesassociated with hypervisor 210, such as a policy specifying that VMs2351-235N are to be automatically restarted upon unexpected terminationand/or upon initialization of hypervisor 210. In addition, oralternatively, hypervisor 210 may manage execution VMs 2351-235N basedon requests received from a device other than host computing device 100.For example, hypervisor 210 may receive an execution instructionspecifying the initiation of execution of first VM 2351 from amanagement device via network communication interface 112 and executethe execution instruction to initiate execution of first VM 2351.

In some embodiments, memory 250 in first virtual hardware platform 2401includes a virtual disk that is associated with or “mapped to” one ormore virtual disk images stored on a disk (e.g., a hard disk or solidstate disk) of host computing device 100. The virtual disk imagerepresents a file system (e.g., a hierarchy of directories and files)used by first VM 2351 in a single file or in a plurality of files, eachof which includes a portion of the file system. In addition, oralternatively, virtual disk images may be stored on one or more remotecomputing devices, such as in a storage area network (SAN)configuration. In such embodiments, any quantity of virtual disk imagesmay be stored by the remote computing devices.

Device driver layer 215 includes, for example, a communication interfacedriver 220 that interacts with network communication interface 112 toreceive and transmit data from, for example, a local area network (LAN)connected to host computing device 100. Communication interface driver220 also includes a virtual bridge 225 that simulates the broadcastingof data packets in a physical network received from one communicationinterface (e.g., network communication interface 112) to othercommunication interfaces (e.g., the virtual communication interfaces ofVMs 2351-235N). Each virtual communication interface for each VM2351-235N, such as network communication interface 255 for first VM2351, may be assigned a unique virtual Media Access Control (MAC)address that enables virtual bridge 225 to simulate the forwarding ofincoming data packets from network communication interface 112. In anembodiment, network communication interface 112 is an Ethernet adapterthat is configured in “promiscuous mode” such that all Ethernet packetsthat it receives (rather than just Ethernet packets addressed to its ownphysical MAC address) are passed to virtual bridge 225, which, in turn,is able to further forward the Ethernet packets to VMs 2351-235N. Thisconfiguration enables an Ethernet packet that has a virtual MAC addressas its destination address to properly reach the VM in host computingdevice 100 with a virtual communication interface that corresponds tosuch virtual MAC address.

Virtual hardware platform 2401 may function as an equivalent of astandard x86 hardware architecture such that any x86-compatible desktopoperating system (e.g., Microsoft WINDOWS brand operating system, LINUXbrand operating system, SOLARIS brand operating system, NETWARE, orFREEBSD) may be installed as guest operating system (OS) 265 in order toexecute applications 270 for an instantiated VM, such as first VM 2351.Virtual hardware platforms 2401-240N may be considered to be part ofvirtual machine monitors (VMM) 2751-275N that implement virtual systemsupport to coordinate operations between hypervisor 210 andcorresponding VMs 2351-235N. Those with ordinary skill in the art willrecognize that the various terms, layers, and categorizations used todescribe the virtualization components in FIG. 2 may be referred todifferently without departing from their functionality or the spirit orscope of the disclosure. For example, virtual hardware platforms2401-240N may also be considered to be separate from VMMs 2751-275N, andVMMs 2751-275N may be considered to be separate from hypervisor 210. Oneexample of hypervisor 210 that may be used in an embodiment of thedisclosure is included as a component in VMware's ESX brand software,which is commercially available from VMware, Inc.

Referring next to FIG. 3, a block diagram illustrates an exemplarycomputing device 304 storing VM templates 309 and data describing VMsinstantiated therefrom. Cloud services 302, an administrator, user 108,and/or other entities interact with computing device 304 to requestinstantiation of child VMs (e.g., such as desktop VMs). Computing device304 configures a parent VM template 310 before instantiating therequested child VMs therefrom to prevent rebooting the child VMs duringsubsequent guest customization, such as described herein.

Computing device 304 represents any device executing instructions (e.g.,as application programs, operating system functionality, or both) toimplement the operations and functionality described and illustratedherein. For example, computing device 304 executes instructions toimplement the operations illustrated in FIG. 4, FIG. 5, and FIG. 8.Computing device 304 may include any computing device or processingunit. For example, computing device may represent a group of processingunits or other computing devices, such as in a cloud computingconfiguration.

Computing device 304 has at least one processor 306 and a memory 308(e.g., a memory area). Processor 306 includes any quantity of processingunits, and is programmed to execute computer-executable instructions forimplementing aspects of the disclosure. The instructions may beperformed by processor 306 or by multiple processors executing withincomputing device 304, or performed by a processor external to computingdevice 304.

Memory 308 includes any quantity of computer-readable media associatedwith or accessible by computing device 304. Memory 308, or portionsthereof, may be internal to computing device 304, external to computingdevice 304, or both. Exemplary memory 308 includes random access memory.

In the example of FIG. 3, memory 308 stores a plurality of VM templates309. In some embodiments, VM templates 309 are arranged in a hierarchy,such as a tree hierarchy. However, aspects of the disclosure areoperable with VM templates 309 stored in any structure. In suchembodiments, VM templates 309 include a plurality of parent VM templates310. In some embodiments, parent VM templates 310 are powered-on. Thepowered-on parent VM templates 310 may be created and maintained bycomputing device 304 and/or by cloud services 302.

In some embodiments, each parent VM template 310 includes a virtualdevice state for one of VMs 235 and a memory state for that VM 235.Memory 308 further stores data describing a plurality of powered-onchild VMs 311.

Computing device 304 further includes storage 307. Storage 307 storesdata describing a plurality of powered-off child VMs 312. Each of thepowered-off child VMs 312 is instantiated, on demand, from one of theplurality of parent VM templates 310. Until then, powered-off child VMs312 do not occupy any memory resources. For example, powered-off childVMs 312 are present in storage 307 and, when powered-on, copy-on-write(COW) share memory pages with parent VMs and enter into memory 308.Storage 307 further stores at least one replica map 316. Replica map 316stores an assignment between each of a plurality of clone VMs and atleast one of a plurality of target hosts (e.g., hosts 100).

Child VMs have one or more properties, characteristics, or dataassociated therewith. Exemplary child VM properties include, but are notlimited to, hostname, IP address, MAC address, domain identity,processor size, and/or memory size. In some embodiments, the child VMproperties for each child VM may be referred to as configuration data.Storage 307 further stores parent VM disks and child VM disks 314 (e.g.,.vmdk files) for use by VMs 235.

In contrast to memory 308, exemplary storage 307 includes one or moredisks.

After instantiation, powered-off child VMs 312 are registered to a cloudoperating system. The cloud operating system is executed in a cloudcomputing configuration. Registration of one of powered-off child VMs312 includes identifying powered-off child VM 312 to the cloud operatingsystem, and occurs before powered-off child VM 312 is powered-on orotherwise executed. In this manner, powered-off child VM 312 is said tobe pre-registered with the cloud operating system. In some embodiments,the cloud operating system is hypervisor 210. By registering powered-offchild VMs 312, the cloud operating system is no longer in the criticalpath when cloud services 302 commission VMs 235, thus reducing theamount of time needed for the child VMs to become available. However,aspects of the disclosure are also operable with registration occurringon the child VM instantiation path.

Alternatively or in addition, aspects of the disclosure include aprovisioning process that instantiates and powers on all child VMs ontarget hosts ahead of time. In such aspects, if an error occurs duringinstantiation and power-on, the error may be caught (and fixed) beforethe child VMs are requested.

Referring next to FIG. 4, a flowchart illustrates an exemplary method400 (e.g., performed by computing device 304 in FIG. 3) to create acustomized clone VM (e.g., customized clone VM 608) before instantiatingchild VMs therefrom. While method 400 is described with reference toexecution by computing device 304 (shown in FIG. 3), it is contemplatedthat method 400 may be performed by any computing device.

At 402, computing device 304 receives a request to provision a pluralityof child VMs. The request may be received from one of cloud services302, an administrator, user 108, or other entity. The request includesdata identifying, for example, a quantity of child VMs to beprovisioned, one of parent VM templates 310, one or more target hosts(e.g., hosts 100), and/or one or more datastores. In response to thereceived request, computing device 304 creates a clone VM from parent VMtemplate 310 identified in the received request at 404.

At 406, computing device 304 applies a first set of customizations tothe created clone VM. The first set of customizations includes one ormore configurations, settings, properties, or the like that, unlikeother customizations, may prompt rebooting of the clone VM. In someembodiments, the first set of customizations represents customizationsthat are common to all child VMs (e.g., common to all desktops in apool). The first set of customizations are defined by, for example, therequesting cloud service 302 (e.g., in the received request),administrator, user 108, and/or other entity. The first set ofcustomizations may also be defined based on the target host and/ordatastore, and may also include default values associated therewith.Application of the first set of customizations may prompt the clone VMto reboot one or more times. For example, computing device 304 (or anagent executing on clone VM) monitors for a reboot request from clone VMduring application of the first set of customizations, and performed areboot of the clone VM upon detecting the reboot request. Exemplarycustomizations in the first set of customizations include, but are notlimited to, adding disks, partitioning the disks, formatting the disks,assigning mount points for the disks, user data redirection (e.g., tonew disks), pagefile and system temporary folder redirection (e.g., tonew disks), and/or other customizations. Pagefile and system temporaryfolder redirection is used for both persistent and non-persistentdesktops, while user data direction is used for persistent desktops.Other exemplary customizations in the first set of customizationsinclude adding a buslogic disk controller (e.g., for some master VMoperating systems). As an example, the following exemplary configurationparameters are added to a configuration file for the clone VM (e.g. a.vmx file):

-   -   guestinfo.uddMountPoint    -   guestinfo.uddSize    -   guestinfo.sddMountPoint    -   guestinfo.sddSize

The clone VM is powered on to complete the consolidated or otherwisecommon customizations (e.g., the first set of customizations). Forexample, a guest customization agent executes on the clone VM to performcommon guest customization based on the specified extra configurationparameters (e.g., disk partitioning, formatting and mount pointassignment). Further, after any added disk volumes are ready per adevice manager executing on the clone VM, data redirection is performed.During this process, there may be one or more reboots involved (e.g., ifthe device manager detects a conflict during device installation).

After applying the first set of customizations, computing device 304suspends execution of customized clone VM 608 to prepare forinstantiation. For example, customized clone VM 608 may be quiesced orpowered off. At 408, computing device 304 instantiates the requestedchild VMs from customized clone VM 608. Aspects of the disclosure areoperable with any fast instantiation routines, such as forking. In someembodiments, forking operations include defining, based on a virtualdevice state of customized clone VM 608, a virtual device state of thechild VM and defining persistent storage for the child VM based onpersistent storage of customized clone VM 608.

After instantiation, each of the child VMs boot, or otherwise beginexecution. At 410, a second set of customizations is applied to at leastone of the child VMs. For example, as each child VM boots up, the childVM contacts computing device 304 to obtain the second set ofcustomizations. In this example, the child VM then applies the secondset of customizations. In another example, computing device 304 appliesthe second set of customizations to the child VM.

The second set of customizations includes one or more configurations,settings, properties or the like that, unlike other customizations, donot prompt rebooting of the child VM. The second set of customizationsare defined by, for example, the requesting cloud service 302 (e.g., inthe received request), administrator, user 108, and/or other entity. Thesecond set of customizations may also be defined based on the targethost and/or datastore, and may also include default values associatedtherewith. In some embodiments, the second set of customizations isdifferent for one or more of the child VMs. The application of thesecond set of customizations to the child VMs do not prompt rebooting ofthe child VMs. Exemplary customizations in the second set ofcustomizations include, but are not limited to, configuring an identityof the child VM such as a computer name, domain join, licenseactivation, media access control (MAC) address, Internet Protocol (IP)address, and the like. In some embodiments, the second set ofcustomizations is collectively referred to as a child VM configuration.

Examples of customizations that attach one or more disks to the clone VMbefore instantiating desktop VMs are described next with reference toFIG. 5. In FIG. 5, a flowchart illustrates an exemplary method 500described as being performed by computing device 304 in FIG. 3. However,it is contemplated that method 500 may be performed by any computingdevice 304.

At 502, computing device 304 receives a request to provision a pluralityof desktop VMs. The desktop VMs provide an end user with an experiencesimilar to, or the same as, that of a personal computer (e.g., laptop,tablet, etc.). The request identifies, at least, one of the plurality ofparent VM templates 310. In response to the received request, computingdevice 304 creates a clone VM from the identified parent VM template 310at 504, attaches one or more disks to the created clone VM at 506, andcustomizes the clone VM to redirect data to the attached disks at 508.In some embodiments, the clone VM is powered on after attaching thedisks, but before customizing the clone VM to redirect data to theattached disks. Further, the clone VM may be rebooted one or more timesduring operations 506 and/or 508.

At 510, computing device 304 instantiates the requested plurality ofdesktop VMs from customized clone VM 608. A VM configuration, or otherset of customizations (e.g., the second set of customizations), isapplied to the instantiated desktop VMs at 512. Applying the VMconfiguration does not prompt or provoke a reboot of the desktop VMs.The VM configuration is obtained and applied in a manner similar to thesecond set of customizations, as described above in FIG. 4.

In some embodiments, each desktop VM may be quiesced, or otherwisesuspended, to create a checkpoint image of the desktop VM, but withoutshutting down the desktop VM for the snapshot and then powering back on(e.g., a reboot). This enables user 108, administrator, or requestingcloud service 302 to create the snapshot without rebooting the desktopVM, and to revert to the checkpoint image at a subsequent, future time.

Referring next to FIG. 6, a block diagram illustrates an exemplary cloudplatform 606 for attaching one or more disks to a clone VM beforeinstantiating desktop VMs. One or more virtual desktop services 602interact with a fast instantiation provisioning engine 604 to scale upor scale down cloud computing resources associated with the virtualdesktop services 602. Fast instantiation provisioning engine 604represents an application programming interface (API) providing virtualdesktop services 602 with access to fast instantiation routinesexecuting on cloud platform 606. Aspects of the disclosure are operablewith any fast instantiation routines. In some embodiments, the fastinstantiation routines include forking routines, such as describedherein.

In the example of FIG. 6, cloud platform 606 includes a plurality ofparent template VMs, or other user template VMs. Each parent template VMincludes a guest operating system. A guest customization agent residesinside each guest operating system. Upon receipt of a request toprovision one or more desktop VMs, a clone VM (e.g., a linked clone) orother internal template VM is prepared from parent template VM. One ormore disks are attached or otherwise added to the clone VM to customizethe clone VM. In the example of FIG. 6, a user data disk and a systemdisposable disk are added to the clone VM. Those skilled in the art willnote that the user data disk is present only for persistent desktops, insome embodiments. The clone VM is powered on, and further configured toredirect data to the two disks. For example, user profile data isredirected to the user data disk, while system temporary data (e.g.,pagefiles) is redirected to the system disposable disk. Other guestcustomization may also be performed. One or more reboots may beperformed during this execution of the guest customization agent. Withsome systems, each of the user data disk and the system disposable diskare stored as .vmdk files. After guest customizations are completed, theclone VM is powered off.

Customized clone VM 608 is a full clone of the clone VM, and a snapshotis taken. Customized clone VM 608, now acting as one of parent templateVMs, is transmitted to, or accessed by, at least one host computingdevice 100. There may be a plurality of host computing devices 100 thataccess the clone VM. A plurality of desktop VMs, such as desktop VM #1through desktop VM #N, are instantiated from customized clone VM 608.When the desktop VMs are powered on, there is no longer any rebootthreat from the device manager as the disk drivers are already in place.

Referring next to FIG. 7, a block diagram illustrates replication ofcustomized clone VM 608 to datastores 704 of target hosts 702. For eachtarget host 702, there may be one or several shared datastores 704(e.g., shared among or between target hosts 702), and/or one or morelocal datastores 704 (e.g., not shared with any other target host 702).In the example of FIG. 7, customized clone VM 608 is created from aselected one of a plurality of parent VM templates 310 (e.g., see FIG. 4and FIG. 5). Customized clone VM 608 is replicated concurrently (e.g.,at approximately the same time) to a plurality of datastores 704 (e.g.,thereby creating replica VMs 706) such that each target host 702 (e.g.,belonging to the same resource pool) has access to at least one ofreplica VMs 706, prior to instantiation of any child VMs therefrom. Forexample, if 2100 desktop VMs are desired across three target hosts 702,computing device 304 replicates customized clone VM 608 to threedatastores 704, each associated with one of the three target hosts 702.Each of the three datastores 704 will store 700 of the desktop VMs, inthis example. However, other allocations of the desktop VMs todatastores 704 are contemplated.

Replication involves copying customized clone VM 608, as opposed tocreating a linked clone VM. Maximizing the concurrency of replicacreations reduces the overall wait time for all linked clone VM (e.g.,child VM) creation on target hosts 702.

Referring next to FIG. 8, a flowchart illustrates an exemplary method800 for using replica map 316 to identify, or create, customized cloneVM 608 from which to instantiate child VMs on target host 702. Whilemethod 800 is described with reference to execution by computing device304 (shown in FIG. 3), it is contemplated that method 800 may beperformed by any computing device. The operations shown in FIG. 8, whenexecuted by processor 306, cause processor 306 to perform consolidatedcustomizations before instantiating desktop VMs using replica VMs 706.

At 802, computing device 304 receives a request to provision a pluralityof child VMs. The request, in this example, identifies one of parent VMtemplates 310 (e.g., a clone VM) and one of target hosts 702. Inresponse to the received request, computing device 304 accesses replicamap 316 storing correspondences or other associations between clone VMsand target hosts 702. In some embodiments, the identified parent VMtemplate 310 and target host 702 are used in combination as a key intoreplica map 316. If the identified target host 702 has a clone VM (e.g.,replica VM 706) associated therewith that corresponds to the requestedparent VM template 310 based on replica map 316 at 804, computing device304 selects the clone VM at 806 to use for instantiation of therequested child VMs.

In another example, the request does not identify the requested parentVM template 310. In such an example, the internal linked clone VMassociated with target host 702 (identified in the request) isconsidered to be parent VM template 310.

In still another example, rather than identifying one of parent VMtemplates 310, the request includes a replica VM identifier associatedwith the desired replica VM 706.

If the identified target host 702 does not have a clone VM associatedtherewith that corresponds to the requested parent VM template 310,computing device 304 proceeds to create replica VM 706. At 808,computing device 304 creates a clone VM from the requested parent VMtemplate 310 and applies at 810 a first set of customizations to thecreated clone VM. As described herein, the first set of customizationsare those customizations that, when applied, may prompt rebooting of thecreated clone VM. At least one datastore 704 accessible by target host702 is selected. Customized clone VM 608 is replicated to the selecteddatastore 704 associated with, or otherwise accessible by, theidentified target host 702 at 812. One single replica VM 706 is createdper target host 702 in some examples, while more than one replica VM 706is created per target host 702 (e.g., to different datastores 704accessible by target host 702) in other examples for load balancing.Replica VM 706 is registered to target host 702. Computing device 304updates replica map 316 at 814 (e.g., inserts an entry into replica map316) to include the correspondence between the newly-created replica VM706 and the identified target host 702 to allow the newly-createdreplica VM 706 to be used to instantiate another child VM at a futuretime.

Computing device 304 also quiesces, or otherwise suspends, the newlycreated replica VM 706 in preparation for instantiation of child VMs. Asnapshot is taken of replica VM 706, and methods of destroying,relocating, migrating, reconfiguring, unregistering, and/or powering offmay be disabled to protect replica VM 706. Replica VM 706 is powered onto get into the forked state. At 816, computing device 304 instantiatesthe requested child VMs from replica VM 706 (e.g., either thepre-existing replica VM 706 or the newly created replica VM 706).Instantiation includes, in some embodiments, forking the requested childVMs from replica VM 706 to create linked clone VMs. Instantiation mayfurther include setting configuration parameters to be applied uponpower-on of child VMs, such as the following:

-   -   guestInfo.machineName    -   guestInfo.machinePassword    -   guestIng.licenseActivation    -   guestInfo.checkpointing

At 818, each of the instantiated child VMs powers on to perform a secondset of customizations (e.g., apply one or more child VM configurations).As described herein, the second set of customizations are thosecustomizations that, when applied, do not prompt or provoke rebooting ofthe child VMs. The second set of customizations may be different foreach child VM, depending on the parameters specified in a configurationfile (e.g., a .vmx file). For example, the MAC address, machine name,and/or machine password may be set based on the presence of fields suchas guestInfo.macAddress, guestInfo.machineName, and/orguestInfo.machinePassword, respectively. If the machine password is set,the machine password is removed from the configuration file, in someembodiments. In another example, the child VM performs licenseactivation if a configuration parameter such asguestInfo.licenseActivation is set to True. Further, the child VM mayperform checkpointing operations to enable fast refresh if aconfiguration parameter such as guestInfo.checkpointing is set to True(e.g., in non-persistent designs). Checkpointing includes quiescing filesystems of the child VM (e.g., flushing to persistent storage), andmaking a file copy of an operating system disk to serve as a checkpointcopy. During a subsequent fast refresh, the operating system disk isreplaced with the checkpoint copy.

Some of the customized child VMs may further be modified or promoted tobe persistent desktop VMs (e.g., not reset at reboot) so that anysubsequent power-on operations (e.g., disk changes) do not conflict withthe forked state of the child VM. The promotion may occur duringmigration of the child VM to another datastore or logical unit number(LUN) device which converts linked clones to full, independent clones.This enables full-clone VMs to be rapidly deployed and made available toend users without any reboots while being gradually converted tofull-clone status (e.g., during a subsequent migration). Fornon-persistent child VMs (e.g., the child VM is reset or refreshed ateach power-down or logoff), there is no need for such promotion.

The operations illustrated in FIG. 4, FIG. 5, and FIG. 8 may beimplemented as computer-executable instructions stored on one or morecomputer-readable storage media.

An example forking operation is next described with reference to FIG. 9.However, those skilled in the art will note that aspects of thedisclosure are operable with any fast instantiation routines. In FIG. 9,a block diagram illustrates forking of the child VMs (e.g., child1 VMand child2 VM) from one of parent VM templates 310. Forking avoids aboot storm by instead consuming resources to power-on a base VM imageonce, and then instantly forking off copies of the pre-booted VM. Inthis manner, the need for hot-spare VMs is eliminated in someembodiments. Further, forked VMs share common memory and disk state,thus eliminating the need to store or de-duplicate redundant copies ofdisk or memory content across common VMs.

In an exemplary forking routine, one of VMs is quiesced (thus becoming apowered-on parent VM template 310), and then a defined quantity of thechild VMs may be created using the memory, disk, and device state imageof parent VM template 310. Such a forking routing may be organized intothree stages: preparing a parent VM, preparing the child VM, andspawning the child VM.

To prepare a parent VM (e.g., a target VM), the parent VM is firstpowered-on and brought into a state from which the child VMs are desiredto begin execution. For example, preparing includes bringing downnetwork interfaces in the parent VM in preparation for an in-guestidentity change. When the parent VM is ready to be forked, a user orscript issues a command via a guest remote procedure call (RPC) tohypervisor 210 requesting the forking. The fork request, in someembodiments, is a synchronous RPC that returns only after the forkprocess has succeeded. Hypervisor 210 handles the guest RPC by quiescingthe parent VM, halting its execution state, and marking all of thememory pages in the parent VM as COW. The memory and disk state of theparent VM are then ready for use by the child VMs. From the perspectiveof the parent VM, upon issuing the guest RPC, the parent VM is quiescedforevermore, never to run another instruction.

To prepare the child VM, the child VM is configured to leverage theexisting memory, device, and disk state of the parent VM. To share thedisk of the parent VM, the child VM is configured with a redo logpointing to the disk of the parent VM as the base disk of the child VM(e.g., similar to a linked clone VM). In addition, the child VM may beconfigured with its own dedicated storage that is not related to theparent VM. For example, the dedicated storage may include a data disk oraccess to shared storage if the child VM desires to persist state instorage other than its redo log.

A configuration file (e.g., .vmx file) associated with the child VM isupdated to indicate that the child VM inherits the memory and devicestate of the parent VM upon power-on. The configuration file may also beupdated with additional information, such as a desired MAC address andIP address for the child VM. The configuration file is registered withthe cloud operating system (e.g., executing on a host), and the child VMis ready to be powered-on on demand.

In some embodiments, the redo log of the child VM is marked asnon-persistent. In such embodiments, upon each power-on, the child VMinherits a fresh copy of the memory, device, and disk state of theparent VM (e.g., re-forks from the quiesced image of the parent VM). Inother embodiments, the redo log of the child VM is marked as persistent.

After preparation, the child VM is ready to be powered-on (e.g.,spawned) upon receipt of a power-on request (e.g., from cloud service302). In response to receipt of such a power-on request, the child VMinherits the memory and device state of parent VM template 310. As such,rather than performing a normal boot process, such as through the basicinput output system (BIOS), the child VM instead resumes from the stateof parent VM template 310. For example, the child VM inherits a COWreference to the memory state of the parent VM template 310. ReferencingCOW memory on the same host eliminates overhead for unmapped pages andresults in a small overhead for mapped pages (e.g., less than onemicrosecond for four kilobyte pages), thus providing fast child VMinstantiation.

Further, by referencing COW memory, the child VM is able to beginexecution in a fraction of a second from the precise instruction (e.g.,fork guest RPC) at which parent VM (from which parent VM template 310was created) was quiesced. From the perspective of the child VM, thechild VM sees the fork guest RPC returning successfully from hypervisor210. The child VM may then be migrated away from parent VM template 310without need for one-to-many migrations (e.g., one-to-many vMotionoperations).

The child VM may then be customized. Customizing the child VM includes,for example, reading and applying a desired configuration state from theconfiguration file specified when preparing the child VM. As describedherein, some embodiments customize the child VM by identifying andapplying a MAC address, IP address, hostname, and other state to thechild VM. Leveraging the customization data, the child VM may then spoofits MAC address to the desired MAC address, update its hostname, IPaddress, etc., and bring up its network interface. The child VM thencontinues execution as a unique VM (e.g., separate from parent VM) withits own identity.

Additional Examples

The following scenarios are merely exemplary and not intended to belimiting in any way.

In one scenario, an application programming interface (API) associatedwith cloud platform is updated to support aspects of the disclosure. Forexample, the same new clone API for forking is used to clone a full VMto enable all replica VMs 706 of the same host to share the same forkedmemory pages after power-on. The API may also be updated to query orverify that a parent VM is successfully in a forked state afterpower-on, to clone the child VM from a forked parent VM, and/or topromote linked clone VM to a full independent VM (e.g., remove forkidentity from the forked VM).

In one example, customized clone VM 608 represents a linked clone VMhaving a small memory footprint (e.g., a delta disk of about fifteenmegabytes). Further, in some embodiments, there is one such customizedclone VM 608 for each of parent VM templates 310. Each of customizedclone VMs 608 may spawn any quantity of the child VMs. In someembodiments, 2000 or more child VMs are spawned from each customizedclone VM 608.

Exemplary Operating Environment

The operations described herein may be performed by a computer orcomputing device. The computing devices communicate with each otherthrough an exchange of messages and/or stored data. Communication mayoccur using any protocol or mechanism over any wired or wirelessconnection. A computing device may transmit a message as a broadcastmessage (e.g., to an entire network and/or data bus), a multicastmessage (e.g., addressed to a plurality of other computing devices),and/or as a plurality of unicast messages, each of which is addressed toan individual computing device. Further, in some embodiments, messagesare transmitted using a network protocol that does not guaranteedelivery, such as User Datagram Protocol (UDP). Accordingly, whentransmitting a message, a computing device may transmit multiple copiesof the message, enabling the computing device to reduce the risk ofnon-delivery.

By way of example and not limitation, computer readable media comprisecomputer storage media and communication media. Computer storage mediainclude volatile and nonvolatile, removable and non-removable mediaimplemented in any method or technology for storage of information suchas computer readable instructions, data structures, program modules orother data. Computer storage media are tangible, non-transitory, and aremutually exclusive to communication media. In some embodiments, computerstorage media are implemented in hardware. Exemplary computer storagemedia include hard disks, flash memory drives, digital versatile discs(DVDs), compact discs (CDs), floppy disks, tape cassettes, and othersolid-state memory. In contrast, communication media typically embodycomputer readable instructions, data structures, program modules, orother data in a modulated data signal such as a carrier wave or othertransport mechanism, and include any information delivery media.

Although described in connection with an exemplary computing systemenvironment, embodiments of the disclosure are operative with numerousother general purpose or special purpose computing system environmentsor configurations. Examples of well-known computing systems,environments, and/or configurations that may be suitable for use withaspects of the disclosure include, but are not limited to, mobilecomputing devices, personal computers, server computers, hand-held orlaptop devices, multiprocessor systems, gaming consoles,microprocessor-based systems, set top boxes, programmable consumerelectronics, mobile telephones, network PCs, minicomputers, mainframecomputers, distributed computing environments that include any of theabove systems or devices, and the like.

Embodiments of the disclosure may be described in the general context ofcomputer-executable instructions, such as program modules, executed byone or more computers or other devices. The computer-executableinstructions may be organized into one or more computer-executablecomponents or modules. Generally, program modules include, but are notlimited to, routines, programs, objects, components, and data structuresthat perform particular tasks or implement particular abstract datatypes. Aspects of the disclosure may be implemented with any number andorganization of such components or modules. For example, aspects of thedisclosure are not limited to the specific computer-executableinstructions or the specific components or modules illustrated in thefigures and described herein. Other embodiments of the disclosure mayinclude different computer-executable instructions or components havingmore or less functionality than illustrated and described herein.

Aspects of the disclosure transform a general-purpose computer into aspecial-purpose computing device when programmed to execute theinstructions described herein.

The embodiments illustrated and described herein as well as embodimentsnot specifically described herein but within the scope of aspects of theinvention constitute exemplary means for configuring parent VM template310 before instantiating child VMs therefrom to prevent rebooting thechild VMs during customization. For example, one or more of theembodiments contemplate means for receiving, by computing device, arequest to provision a plurality of desktop VMs, means for creating theclone VM from parent VM template 310 in response to the receivedrequest, means for attaching one or more disks to the created clone VM,means for customizing the clone VM to redirect data to the attacheddisks, means for instantiating the plurality of desktop VMs fromcustomized clone VM 608, and means for applying a VM configuration to atleast one of the instantiated plurality of desktop VMs without rebootingthat desktop VM.

At least a portion of the functionality of the various elementsillustrated in the figures may be performed by other elements in thefigures, or an entity (e.g., processor, web service, server, applicationprogram, computing device, etc.) not shown in the figures.

In some embodiments, the operations illustrated in the figures may beimplemented as software instructions encoded on a computer readablemedium, in hardware programmed or designed to perform the operations, orboth. For example, aspects of the disclosure may be implemented as asystem on a chip or other circuitry including a plurality ofinterconnected, electrically conductive elements.

The order of execution or performance of the operations in embodimentsof the disclosure illustrated and described herein is not essential,unless otherwise specified. That is, the operations may be performed inany order, unless otherwise specified, and embodiments of the disclosuremay include additional or fewer operations than those disclosed herein.For example, it is contemplated that executing or performing aparticular operation before, contemporaneously with, or after anotheroperation is within the scope of aspects of the disclosure.

When introducing elements of aspects of the disclosure or theembodiments thereof, the articles “a,” “an,” “the,” and “said” areintended to mean that there are one or more of the elements. The terms“comprising,” “including,” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements. The term “exemplary” is intended to mean “an example of”

Having described aspects of the disclosure in detail, it will beapparent that modifications and variations are possible withoutdeparting from the scope of aspects of the disclosure as defined in theappended claims. As various changes could be made in the aboveconstructions, products, and methods without departing from the scope ofaspects of the disclosure, it is intended that all matter contained inthe above description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

We claim:
 1. A system for configuring a parent virtual machine (VM)template before instantiating child VMs therefrom to prevent rebootingthe child VMs during customization, said system comprising: memoryassociated with a computing device, said memory storing a plurality ofparent VM templates; and a processor programmed to: receive, by thecomputing device, a request to provision a plurality of desktop VMs, therequest identifying one of the plurality of parent VM templates; inresponse to the received request, create a clone VM from the identifiedparent VM template; attach one or more disks to the created clone VM;power on the clone VM with the attached one or more disks; customize theclone VM to redirect data to the attached disks; instantiate theplurality of desktop VMs from the customized clone VM; and apply a VMconfiguration to at least one of the instantiated plurality of desktopVMs without rebooting the at least one of the instantiated plurality ofdesktop VMs.
 2. The system of claim 1, further comprising storageincluding a replica map that stores an assignment between each of aplurality of clone VMs and at least one of a plurality of target hosts.3. The system of claim 2, wherein the processor is further programmed toupdate the replica map with an assignment between the customized cloneVM and the target host.
 4. The system of claim 3, wherein the processoris further programmed to: receive a request to provision another desktopVM, the request identifying one of the plurality of target hosts; selectone of the plurality of clone VMs from the replica map based on theidentified one of the plurality of target hosts; and instantiate theanother desktop VM from the selected one of the plurality of clone VMs.5. The system of claim 1, wherein the processor is further programmedto: quiesce the at least one of the instantiated plurality of desktopVMs; and create a checkpoint image of the quiesced desktop VM to enablea user to revert to the created checkpoint image at a subsequent time.6. The system of claim 1, wherein the processor is further programmed topower on the clone VM after attaching the one or more disks and beforecustomizing the clone VM.
 7. The system of claim 1, wherein theprocessor is further programmed to reboot the clone VM one or more timesduring customization.
 8. A method comprising: receiving, by a computingdevice, a request to provision a plurality of child virtual machines(VMs), the request identifying a parent VM template; in response to thereceived request, creating a clone VM from the parent VM template;applying, by the computing device, one or more customizations thatprompt rebooting of the clone VM, wherein applying the one or morecustomizations comprises: attaching, by the computing device, one ormore disks to the created clone VM before rebooting of the clone VM,rebooting the clone VM with the one or disks attached, and customizingthe clone VM to redirect data to the attached disks; instantiating theplurality of child VMs from the customized clone VM; and applying achild VM configuration to at least one of the instantiated plurality ofchild VMs without rebooting the at least one of the instantiatedplurality of child VMs.
 9. The method of claim 8, further comprisingpartitioning and formatting the one or more disks.
 10. The method ofclaim 8, further comprising assigning a mount point to each of the oneor more disks.
 11. The method of claim 8, wherein attaching the one ormore disks comprises attaching a user data disk and a system disposabledisk.
 12. The method of claim 11, wherein customizing the clone VM toredirect data to the attached disks comprises redirecting user profiledata to the user data disk and redirecting system temporary data to thesystem disposable disk.
 13. The method of claim 8, further comprising:monitoring for a reboot request during the applying of the one or morecustomizations; and on detecting the reboot request, performing a rebootof the clone VM.
 14. The method of claim 8, further comprisingsuspending the customized clone VM, and wherein instantiating theplurality of child VMs from the customized clone VM comprises forkingeach of the plurality of child VMs by: defining, based on a virtualdevice state of the suspended clone VM, a virtual device state of thechild VM; and defining persistent storage for the child VM based onpersistent storage of the suspended clone VM.
 15. The method of claim 8,further comprising: quiescing the at least one of the instantiatedplurality of child VMs; and creating a checkpoint image of the quiescedchild VM to enable a user to revert to the created checkpoint image at asubsequent time.
 16. One or more non-transitory computer-readablestorage media including computer-executable instructions that, whenexecuted, cause at least one processor to consolidate commoncustomization before instantiating child virtual machines (VMs) usingreplicas, comprising: receiving, by a computing device, a request toprovision a plurality of child VMs, the request identifying a parent VMtemplate and a target host; in response to the received request,creating a clone VM from the parent VM template; applying a first set ofcustomizations to the created clone VM that prompt rebooting of thecreated clone VM, wherein the first set of customizations compriseattaching one or more disks to the created clone VM and powering on thecustomized clone VM with the attached one or more disks; replicating thecustomized clone VM to a datastore accessible by the target host; andinstantiating the plurality of child VMs from the replicated VM storedin the datastore, wherein each of the instantiated plurality of childVMs powers on to perform a second set of customizations withoutrebooting.
 17. The non-transitory computer storage media of claim 16,wherein each of the instantiated plurality of child VMs performs thesecond set of customizations by applying a child VM configurationwithout rebooting the child VM.
 18. The non-transitory computer storagemedia of claim 16, wherein the computer-executable instructions furthercause the processor to quiesce the replicated clone VM prior toinstantiating the plurality of child VMs.
 19. The non-transitorycomputer storage media of claim 16, wherein the computer-executableinstructions cause the processor to replicate the customized clone VM toa plurality of datastores at the same time prior to instantiating theplurality of child VMs.
 20. The non-transitory computer storage media ofclaim 19, wherein the computer-executable instructions further cause theprocessor to instantiate another child VM from a replica VM previouslyassociated with the target host.